hi, I'm a fedora 8 user. i changed the name of its root's home to a new name 'HOME' from desktop. Now, i'm unable to login.when i write root in username giving password , it is showing error.
how to go inside??? what to do??

Try logging in as a normal user (you did create a normal user account when you installed linux, didn't you?) and open a command line. Type:
That is only if you had changed /root to /HOME in the first place.
Then you should be able to log in.
You shouldn't really change the names of any system folders or anything connected with root. Always log in as a normal user, and use the commands 'su' or 'sudo' to perform necessary system tasks. This will save you A LOT OF problems.

edit: you can also use an installation disk (go into rescue mode) or a live cd to change the name back to /root

sycamorex, you are missing part of the picture, I have just read another post by the OP who states that he has overwritten /etc with the information from a previous installation, as such he is probably using the wrong password for root (amongst other things).

A file that specifies each user's home directory is /etc/passwd
That's my entry for root's account:
Using the above methods to get to the system you can edit this file.

ok, yeah now I read the other post as well. I don't think coping /etc directory of one system using it for a different system is a good idea. It can be a great number of problems with it.
But assuming the passwords are the same, it should work, shouldn't it?

Well, assuming the file permissions for files in /etc are set correctly, and that the root password is known for the old image, then yes I suppose it should work.

However, there are a lot of unknowns, do the non-root users exist with the same user ids and group ids? Are the same applications installed? etc, etc (pardon the pun).

Generally I would just advise against it.

I assume that the OP has just installed the new system and then overwrote the /etc directory. This means that the easiest and probably best solution would be to reinstall
the whole system again and then examine the differences between the old and new /etc configuration files individually and if necessary implement modifications one step at a time.
Even if changing /etc/passwd succeeds, as Disillusionist said, there are too many unknowns.